Understanding Arc Flash rating requirement

[MikeChaco]

Hello, my name is Mike and I am a Maintenance Tech. I AM NOT AN ELECTRICIAN.

I work on large pumps and motors. They are 1200HP 4160v. We had all of our switch gear rated and labeled, but I would like some clarification.
I have gotten conflicting info about our Arc Flash ratings.

I am trying to find out what PPE is required to operate the disconnect for the attached rated equipment.

Please let me know if more information is required.
Thank you

 

[jtinge]

Hello, my name is Mike and I am a Maintenance Tech. I AM NOT AN ELECTRICIAN.

I work on large pumps and motors. They are 1200HP 4160v. We had all of our switch gear rated and labeled, but I would like some clarification.
I have gotten conflicting info about our Arc Flash ratings.

I am trying to find out what PPE is required to operate the disconnect for the attached rated equipment.

Please let me know if more information is required.
Thank you

Based on your question, you first need to determine if you are even qualified to work on this equipment. The NEC and NFPA 70E, Standard for Electrical Safety in the Workplace define qualified person as follows:

Qualified Person. One who has demonstrated skills and
knowledge related to the construction and operation of
electrical equipment and installations and has received
safety training to identify and avoid the hazards involved.

Additionally, NFPA 70E states that a qualified person should be trained as follows:

(1) Qualified Person. A qualified person shall be trained
and knowledgeable in the construction and operation of
equipment or a specific work method and be trained to
identify and avoid the electrical hazards that might be
present with respect to that equipment or work method.

(a) Such persons shall also be familiar with the proper
use of the special precautionary techniques, applicable electrical
policies and procedures, PPE, insulating and shielding
materials, and insulated tools and test equipment. A
person can be considered qualified with respect to certain
equipment and methods but still be unqualified for others.
(b) Such persons permitted to work within the limited
approach boundary shall, at a minimum, be additionally
trained in all of the following:
(1) Skills and techniques necessary to distinguish exposed
energized electrical conductors and circuit parts from
other parts of electrical equipment
(2) Skills and techniques necessary to determine the nominal
voltage of exposed energized electrical conductors
and circuit parts
(3) Approach distances specified in Table 130.4(D)(a) and
Table 130.4(D)(b) and the corresponding voltages to
which the qualified person will be exposed
(4) Decision-making process necessary to be able to do the
following:
a. Perform the job safety planning
b. Identify electrical hazards
c. Assess the associated risk
d. Select the appropriate risk control methods from
the hierarchy of controls identified in 110.1(G),
including personal protective equipment

The last one includes knowing how to determine the correct PPE. If you don't know how to assess the hazard and select the appropriate risk control methods, including selecting the correct PPE, or if you haven't had electrical safety training, I would say you are not qualified to do the work and need to get electrical safety training as a minimum.

 

[Strathead]

Based on your question, you first need to determine if you are even qualified to work on this equipment. The NEC and NFPA 70E, Standard for Electrical Safety in the Workplace define qualified person as follows:

Qualified Person. One who has demonstrated skills and
knowledge related to the construction and operation of
electrical equipment and installations and has received
safety training to identify and avoid the hazards involved.

Additionally, NFPA 70E states that a qualified person should be trained as follows:

(1) Qualified Person. A qualified person shall be trained
and knowledgeable in the construction and operation of
equipment or a specific work method and be trained to
identify and avoid the electrical hazards that might be
present with respect to that equipment or work method.

(a) Such persons shall also be familiar with the proper
use of the special precautionary techniques, applicable electrical
policies and procedures, PPE, insulating and shielding
materials, and insulated tools and test equipment. A
person can be considered qualified with respect to certain
equipment and methods but still be unqualified for others.
(b) Such persons permitted to work within the limited
approach boundary shall, at a minimum, be additionally
trained in all of the following:
(1) Skills and techniques necessary to distinguish exposed
energized electrical conductors and circuit parts from
other parts of electrical equipment
(2) Skills and techniques necessary to determine the nominal
voltage of exposed energized electrical conductors
and circuit parts
(3) Approach distances specified in Table 130.4(D)(a) and
Table 130.4(D)(b) and the corresponding voltages to
which the qualified person will be exposed
(4) Decision-making process necessary to be able to do the
following:
a. Perform the job safety planning
b. Identify electrical hazards
c. Assess the associated risk
d. Select the appropriate risk control methods from
the hierarchy of controls identified in 110.1(G),
including personal protective equipment

The last one includes knowing how to determine the correct PPE. If you don't know how to assess the hazard and select the appropriate risk control methods, including selecting the correct PPE, or if you haven't had electrical safety training, I would say you are not qualified to do the work and need to get electrical safety training as a minimum.

Does operating a safety switch require PPE? I don't think so. In fact, one of the reasons it is there is to shut down equipment with moving parts in case of emergency need.

 

[iwire]

Does operating a safety switch require PPE?

I believe it can be required.

I don't think so. In fact, one of the reasons it is there is to shut down equipment with moving parts in case of emergency need.

I disagree with that. The NEC requires the switch for servicing the equipment not as an emergency switch. We can lock the service switch on with a pad lock if we choose.

 

[jtinge]

Does operating a safety switch require PPE? I don't think so. In fact, one of the reasons it is there is to shut down equipment with moving parts in case of emergency need.

My point was that if you had to ask, you probably were not qualified. A qualified person would have the skills and knowledge and the safety training to assess the hazard or lack thereof and determine if PPE was needed.

 

[Saturn_Europa]

Based on your question, you first need to determine if you are even qualified to work on this equipment. The NEC and NFPA 70E, Standard for Electrical Safety in the Workplace define qualified person as follows:

Qualified Person. One who has demonstrated skills and
knowledge related to the construction and operation of
electrical equipment and installations and has received
safety training to identify and avoid the hazards involved.

Additionally, NFPA 70E states that a qualified person should be trained as follows:

(1) Qualified Person. A qualified person shall be trained
and knowledgeable in the construction and operation of
equipment or a specific work method and be trained to
identify and avoid the electrical hazards that might be
present with respect to that equipment or work method.

(a) Such persons shall also be familiar with the proper
use of the special precautionary techniques, applicable electrical
policies and procedures, PPE, insulating and shielding
materials, and insulated tools and test equipment. A
person can be considered qualified with respect to certain
equipment and methods but still be unqualified for others.
(b) Such persons permitted to work within the limited
approach boundary shall, at a minimum, be additionally
trained in all of the following:
(1) Skills and techniques necessary to distinguish exposed
energized electrical conductors and circuit parts from
other parts of electrical equipment
(2) Skills and techniques necessary to determine the nominal
voltage of exposed energized electrical conductors
and circuit parts
(3) Approach distances specified in Table 130.4(D)(a) and
Table 130.4(D)(b) and the corresponding voltages to
which the qualified person will be exposed
(4) Decision-making process necessary to be able to do the
following:
a. Perform the job safety planning
b. Identify electrical hazards
c. Assess the associated risk
d. Select the appropriate risk control methods from
the hierarchy of controls identified in 110.1(G),
including personal protective equipment

The last one includes knowing how to determine the correct PPE. If you don't know how to assess the hazard and select the appropriate risk control methods, including selecting the correct PPE, or if you haven't had electrical safety training, I would say you are not qualified to do the work and need to get electrical safety training as a minimum.

I agree. In my experience it has always been the employer that qualified the person. In my case, checking the box on training, being assigned safety equipment and having electrical tasks in ones job description almost always made the individual qualified up to Haz Cat 2. There was never a demonstration of skills or a skills test.

I was a "qualified person" long before I held an electrical credential.

What version of the NEC 70E is your employer using? We still use the 2012 version which is tasked base. We adopted a blanket statement that no employee may perform a task that is higher than Cat 2. From table 130.7(c)(15)(a) NEC 70E 2012 Edition: Metal Clad Switch Gear 1kV-38kV Max 35 kA short circuit current available, .2 sec clearing time etc. etc. : circuit breaker operation with doors closed is a Cat 2.

Where it specifically rates a 1200 hp pump, meduim voltage disconnect..... I do not know.

It is my understanding that the 2015 Edition is not tasked based and is based solely on available energy/arc risk. So your facility will have to have an arc analysis done and all equipment labeled with PPE requirements.

 

[Saturn_Europa]

Hello, my name is Mike and I am a Maintenance Tech. I AM NOT AN ELECTRICIAN.

I work on large pumps and motors. They are 1200HP 4160v. We had all of our switch gear rated and labeled, but I would like some clarification.
I have gotten conflicting info about our Arc Flash ratings.

I am trying to find out what PPE is required to operate the disconnect for the attached rated equipment.

Please let me know if more information is required.
Thank you

Another question is .......what are you doing once the disconnect is down?

Are you adjusting the packing? OR........

Are you unwiring the motor?

If you are exposing yourself to possibly live electrical parts..........you must have the proper meters and gear.....especially with 4160v. Testing for voltage on 4160 in the NFPA 70E 2012 edition is a Cat 4 EVEN if the disconnect is down!

 

[jtinge]

It is my understanding that the 2015 Edition is not tasked based and is based solely on available energy/arc risk. So your facility will have to have an arc analysis done and all equipment labeled with PPE requirements.

The 2015 Edition did not eliminate tasks, it eliminated Hazard Risk Categories (HRC) and split them into a task table to determine if PPE is required or not and a table that tells you what PPE to use based on an Arc Flash PPE category. If an incident energy (IE) assessment has been made and documented on an arc flash hazard label, select PPE based on the IE shown on the label.

 

[petersonra]

A qualified person would have the skills and knowledge and the safety training to assess the hazard or lack thereof and determine if PPE was needed.

In general I agree with this assessment.

 

[Saturn_Europa]

The 2015 Edition did not eliminate tasks, it eliminated Hazard Risk Categories (HRC) and split them into a task table to determine if PPE is required or not and a table that tells you what PPE to use based on an Arc Flash PPE category. If an incident energy (IE) assessment has been made and documented on an arc flash hazard label, select PPE based on the IE shown on the label.

Thank you for the clarification.

 

[Strathead]

My point was that if you had to ask, you probably were not qualified. A qualified person would have the skills and knowledge and the safety training to assess the hazard or lack thereof and determine if PPE was needed.

For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available. At what point would PPE not be required if it is for this. Are we going to have to wear PPE to unplug a vacuum cleaner next? And, if so, are you OK with that?

 

[jtinge]

For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available. At what point would PPE not be required if it is for this. Are we going to have to wear PPE to unplug a vacuum cleaner next? And, if so, are you OK with that?

You are asking basic questions that a qualified person would be able to answer. The fact that you are asking means as a minimum you need to have some basic electrical safety training.


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[Strathead]

You are asking basic questions that a qualified person would be able to answer. The fact that you are asking means as a minimum you need to have some basic electrical safety training.


Sent from my iPhone using Tapatalk

Not a valid answer. If you are going to assert that I need basic electrical training then it is incumbent on you to cite a valid source that shows the energy levels available from a listed safety switch properly closed is enough to warrant PPE and what level of PPE that is. I have a copy of NFPA 70E sitting here waiting for you to cite the section. I can also refer to my OSHA 30 training study material that should have qualified me to answer this basic question, but I guess I missed that part. Yes that last is sarcastic, but if I am wrong I do actually want to know, but just because someone said so isn't good enough.

 

[jtinge]

If you look at what I said, I said as a minimum you need electrical safety training. This is called out in the definition of qualified person.


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[wbdvt]

For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available. At what point would PPE not be required if it is for this. Are we going to have to wear PPE to unplug a vacuum cleaner next? And, if so, are you OK with that?

Hello, my name is Mike and I am a Maintenance Tech. I AM NOT AN ELECTRICIAN.

I work on large pumps and motors. They are 1200HP 4160v. We had all of our switch gear rated and labeled, but I would like some clarification.
I have gotten conflicting info about our Arc Flash ratings.

I am trying to find out what PPE is required to operate the disconnect for the attached rated equipment.

Please let me know if more information is required.
Thank you

Returning to the OPs question, there are basically 4 items to answer if PPE is required for a task. See NFPA 70E-2015 Table 130.7(C)(15)(A)(a) but in a nutshell it says that arc flash ppe is not required for normal operation of a circuit breaker or switch if:

1. The equipment is properly installed
2. The equipment is properly maintained
3. All equipment doors are closed and latched
4. There is no evidence of impending failure

 

[mayanees]

What version of the NEC 70E is your employer using? We still use the 2012 version which is tasked base.

NFPA 70E is a national consensus safety standard and comes into effect when is issued, unlike NFPA 70 (NEC) that gets "accepted" by the AHJ. So 70E 2015 came into effect August 2014.

The idea is that a safer way to do things has been determined so it should be implemented upon issuance of the standard.

 

[Strathead]

Returning to the OPs question, there are basically 4 items to answer if PPE is required for a task. See NFPA 70E-2015 Table 130.7(C)(15)(A)(a) but in a nutshell it says that arc flash ppe is not required for normal operation of a circuit breaker or switch if:

1. The equipment is properly installed
2. The equipment is properly maintained
3. All equipment doors are closed and latched
4. There is no evidence of impending failure

That is what I was looking for. Thank you.

 

[zog]

For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available.

This is a MV switch, let's not call it a "safety switch". And no they are generally not designed to interrupt the fault current available and some are not even designed to be operated under any load at all which is why you often see them with key interlocks. So per item #1 of a qualified person you have demonstrated a lack of knowledge of the construction and operation of this equipment.

As far as the PPE requirements (per 2012) operating a MV switch with the doors closed is still HRC 2

 

[iwire]

Not a valid answer. If you are going to assert that I need basic electrical training then it is incumbent on you to cite a valid source that shows the energy levels available from a listed safety switch properly closed is enough to warrant PPE and what level of PPE that is. I have a copy of NFPA 70E sitting here waiting for you to cite the section. I can also refer to my OSHA 30 training study material that should have qualified me to answer this basic question, but I guess I missed that part. Yes that last is sarcastic, but if I am wrong I do actually want to know, but just because someone said so isn't good enough.

Besides what other people have said I will ask you this.

When you turn off the switch how do you do the next required step which is verifying the power is off?

You are required to wear PPE for that step.

 

[MikeChaco]

Thankyou for the replies.

The image of the Arc rating label did not get uploaded.

I am doingvarious maintenance procedures, including adjusting packings but that isdone with pump running.

My issue is I have been told 2 different things from ourelectricians. 1 says hazard is only when cover is off, I asked anelectrical engineer and he agreed. The other says a Cat 2, 25cal suit isneeded to throw the disconnect with door closed. I read NFPA 70e Table 130.7to require Cat 2. For Metal Clad switch gear 1kV and above.

Our labels do not say with cover on or off. To me that should mean asconditions are currently.

My goal here is to start an Arc Flash PPE program. I am attempting to have my company supply, or assist in the cost, of Arc Flash clothing. We work in buildings that are full of equipment. Just being in the building makes us in the boundaries.

I am not trying to rewire cabinets here, just trying to understand these labels correctly. I feel throwing a disconnect puts me in harms way, and I am trying to validate or dismiss these concerns.


One of the labels on our gear reads as follows;

QUALIFIED WORKERS ONLY
PPE REQUIRED
438 inch Flash Hazard Boundary
13.6 cal/cm2 Flash Hazard at 36 inches

Category 3 FR Shirt & Pants with FR Coverall with combined AR of at least 25, Hardhat, Hearing Protection, Safety Glasses, Flash Suit Hood, Arc-rated Gloves & leather work shoes

​

4160 VAC Shock Hazard when cover is removed
1 Class Glove with Leather Protectors
60 inch Limited Approach (Fixed Circuit)
26 inch Restricted Approach
7 inch Prohibited Approach